Light weight, high grade 6 volt 3 watt dynamo front hub with easy to use quick release. The Shimano Nexus 3N72 6v 3.0w QR Dynamo Front Hub Provides bright illumination for safer night riding without the need and expense of replacing batteries. Important weight savings are made by using an efficient and light weight aluminium coil structure, Labyrinth and contact sealing – low-friction seals and internal grease sleeve effectively shut out water, mud, and dirt without affecting rotational smoothness increasing service life. Borozon treated bearing races – super mirror finish bearing races reduce friction and provide a more precise bearing action. Push-in wiring harnesses make installation fast and easy. All in a anodised forged aluminium hub shell. Comes with an easy to use quick release skewer. For use with rim brakes. Average weight 558g.